1. Field of the Invention
The present invention is directed to a therapy apparatus for treating a patient with focused acoustic waves, of the type having a source of focused acoustic waves that converge in a focus zone and a locating system for locating a therapeutically relevant region in the body of the patient, the locating system including a graphic display for an image of the therapeutically relevant region.
2. Description of the Prior Art
Acoustic wave systems are employed, for example, for treating stone pathologies (lithotripsy), tumors and bone pathologies (osteorestoration). One proceeds in the treatment that the therapeutically relevant region of the patient is first localized with the locating system, the source of acoustic waves and the body of the patient are then positioned relative to one another such that the therapeutically relevant region is located in the focus of the acoustic waves, and finally the therapeutically relevant region is charged with acoustic waves in the required way. The alignment of the source of acoustic waves and of the body of the patient relative to one another thereby ensues with the assistance of a mark mixed into the image on the graphic display, this mark indicating the position of the center of the focus zone of the acoustic waves in the image generated with the locating means. It has been shown that the most beneficial alignment of the source of acoustic waves and of the body of the patient relative to one another for producing a successful outcome to the therapy cannot always be found in this way.
In order to alleviate this situation, a therapy system disclosed in European Application 0 449 179 provides circuitry for mixing a contour of the focus zone being portrayed in the image, which contour defines a boundary outside of which the acoustic waves fall below a threshold with respect to an acoustic characteristic. The contour is displayed true to position and true to scale. The threshold is that threshold at which and above which the desired outcome of the therapy occurs. That region within which therapy can be successfully accomplished can thus be directly recognized in the image of the display. It is thus easily possible to align the source of acoustic waves and the body of the patient relative to one another such that the contour of the focus zone within which successful therapy can be accomplished and the therapeutically relevant region are aligned such relative to one another so that an optimally beneficial charging of the therapeutically relevant region with the focused acoustic waves is achieved. Such optimally beneficial charging means that the effect of the acoustic waves is essentially limited to the therapeutically relevant region and damage to the tissue surrounding this region is precluded to the greatest extent. It can be seen that the alignment of the source of acoustic waves and the body of the patient relative to one another found in this way will deviate in many cases from that alignment that is achieved in convention systems wherein only the center of the focus zone is marked.